Transcatheter prosthetic heart valve and delivery system

ABSTRACT

A prosthetic heart valve for an endoprosthesis used in the treatment of a stenotic heart valve and/or a heart valve insufficiency. The prosthetic heart valve comprises a plurality of leaflets (3,4,5) which are able to switch between their open and close position in response to the blood flow through the heart. The leaflets are attached into a collapsible wire valve frame involving a stent part (1) and a wire mesh part (2) that complement each other in many ways. The prosthetic valve comprises additional elements (6) for its correct positioning and stabilization.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage entry of InternationalApplication No. PCT/EP2015/077856, filed on Nov. 26, 2015, which claimspriority to Greek Patent Application No. 20140100595 filed on Nov. 26,2014, the disclosures of each of which are hereby incorporated byreference herein in their entirety.

FIELD OF THE INVENTION

The invention generally relates to devices for cardiovascular treatment.More specifically, the invention generally relates to devices forpercutaneous heart valve replacement/implantation.

BACKGROUND OF THE INVENTION

Valvular heart disease is common and involves considerable mortality andmorbidity. Surgical replacement of the failing valve is the treatment ofchoice when the disease progresses and certain criteria are fulfilled.However, it is not uncommon patients fulfilling the criteria for thistreatment to be rejected due to a perceived unacceptably high surgicalrisk for a variety of reasons such as advanced age and comorbidities.For some it is their decision to deny this treatment. These factorsdrove the development of prosthetic heart valve devices that can beimplanted percutaneously with guiding catheters. Many such devices forthe treatment of aortic valve stenosis have gained regulatory approvalsand are already successfully and widely used offering clinical andsurvival benefits in many patients. Recently, we have seen the firstdevice gaining regulatory approval for the percutaneous treatment ofaortic valve insufficiency.

Aortic and mitral valve disease (stenosis and/or insufficiency) areequally common but despite the success in developing percutaneousprosthetic valves for the aortic valve, developing a device forpercutaneously replacing the mitral valve have been challenging andproblematic. The main reason is the much more complex and uneven anatomyof the mitral valve.

Apparently, the development of such a device for the percutaneousreplacement of the mitral valve would be of great benefit for manypatients.

This invention provides numerous alternative solutions to overcome theseproblems and develop a successful percutaneously delivered prostheticmitral valve. Some of the solutions described could be used for similarprosthetic devices for implantation in other heart valves.

SUMMARY OF THE INVENTION

The invention relates to a prosthetic heart valve for an endoprosthesisused in the treatment of a stenotic heart valve and/or a heart valveinsufficiency. The prosthetic heart valve comprises a plurality ofleaflets, which consist of a natural and/or synthetic material and arebeing able to switch between their open and close position in responseto the blood flow through the heart. The leaflets are attached into acollapsible wire valve frame involving a stent part and a wire mesh partthat complement each other in many ways. The frame has a body thatdefines a lumen to its inside. The exterior portion of the frame hasfeatures that serve for its conformation and stabilization/anchoring inthe anatomic structures it contacts. When the endoprosthesis apparatusis expanded within the intended failing native heart valve it replacesit and resumes its function.

The endoprosthesis is contained in a sheathed capsule and is insertedinto the body and advanced to the intended location with a deliverysystem for percutaneously deploying a prosthetic heart valve. Thissystem apart from the sheathed capsule includes an inner shaft assembly,and a handle maintaining control knobs that enable independent movementof the various parts of the sheathed capsule and the endoprosthesis. Thehandle functions allow for gradual release and deployment of theendoprosthesis, but also can recapture the endoprosthesis and safelyremove it out of the body even after its complete deployment to its fullfunctional status.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a first embodiment of a prosthetic valve according to thepresent invention.

FIG. 2 shows a further embodiment of a prosthetic valve according to thepresent invention.

FIG. 3 shows one way of releasing a prosthetic valve according to theinvention from its capsule.

FIG. 4 shows another embodiment of a prosthetic valve according to thepresent invention.

FIG. 5 shows another embodiment of a prosthetic valve according to thepresent invention.

FIG. 6 shows another embodiment of a prosthetic valve according to thepresent invention.

FIG. 7 shows another embodiment of a prosthetic valve according to thepresent invention.

FIG. 8 shows another embodiment of a prosthetic valve according to thepresent invention.

FIG. 9 shows the positioning of a prosthetic valve according to thepresent invention in a patient's heart.

FIG. 10 shows an embodiment of a catheter for the delivery of aprosthetic valve according to the present invention.

FIG. 11 shows the initial part of a transapical deployment of aprosthetic valve according to the present invention.

FIG. 12 shows a transapically deployed prosthetic valve according to thepresent invention.

FIG. 13 shows a further embodiment of a catheter for the delivery of aprosthetic valve according to the present invention.

FIG. 14 shows one way of releasing a prosthetic valve according to theinvention from its capsule.

FIG. 15 shows the initial part of a transatrial/transeptal deployment ofa prosthetic valve according to the present invention.

FIG. 16 shows a transatrially/transeptally deployed prosthetic valveaccording to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Transcatheter Mitral Valve

This prosthetic heart valve and its delivery system are intended for usein the treatment of mitral valve insufficiency and/or mitral valvestenosis. The delivery method is retrograde (the approach of thediseased mitral valve is achieved from within the leftventricle-transapical access and against the flow of the blood) orantegrade (the approach of the diseased mitral valve is achieved fromwithin the left atrium after direct surgical approach or transeptalpuncture and along with the flow of the blood), with the use ofspecifically designed for each access delivery systems. Theendoprosthesis comprises of a plurality of leaflets attached to acollapsible wire frame. This frame integrates a stent part and a braidedand/or flat wire mesh part that complement each other in many ways. Thecombination of these two different resources in building the frame ofthe transcatheter valves described in this invention is very importantand it is believed to solve many of the problems encountered to date forthe development of a successful percutaneous prosthetic mitral valve.The stent part towards its ventricular end and the wire mesh parttowards its atrial end. The wire mesh surrounds the stent at the atrialend and forms a body around the stent extending beyond the atrial end.According to certain embodiments of the present invention, the wire meshextends also longitudinally towards the ventricular end of the stentforming again a body around the stent. There are limitless combinationsof the relative length proportions of the endoprosthesis these parts mayoccupy, and they may overlap. It can have several standardized shapesand sizes. It can even be custom made based on measurements from thepatient's anatomy obtained by medical imaging.

The outer parts of the wire mesh towards the atrium may be braided orflat. The rest of the wire mesh is braided. The stent part that willcover at least the annulus level has a sealing skirt from suitablematerial. The stent part may be cylindrical or conical (and may have aflaring towards the ventricle in order to withstand the excessivesystolic forces exerted on the device with every heart beat). The wiremesh part can incorporate a fabric or other sealing material to make itinstantly impermeable.

The stent part may be made of collapsible nitinol, stainless steel orother material and can self-expand. The wire mesh may be made ofcollapsible nitinol, stainless steel or other material and canself-expand. The advantages of the stent component is that it hasmaximal radial force and thus can appose and stabilize the frameoptimally in areas of the mitral valve this is needed (such as theannulus area). It also provides the areas at which the prosthetic valveleaflets are attached and other structures described later. The wiremesh on the other hand, can better conform and adapt to areas of unevenand unpredictable anatomy and offer optimal sealing of unwanted bloodflow by doing so. The shutting of unwanted blood flow can be instantwhen fabric or other components are incorporated into or on the mesh.The flat wire mesh can expand to larger diameters and reach longer whereneeded without occupying large volumes. The braided wire mesh may expandless but it self-adjusts perfectly to fill in restrained spaces (such asspaces between the mitral valve annulus and the stent part of the frame)and to assume the shape of the anatomy it apposes to (such as the mitralvalve annulus).

The endoprosthesis frame apposes to the intended area and itsanatomically designed shape together with its radial strength and itsother supporting features allow it to steadily fix. In addition, theframe has particular features on its outer surface that allow deployingthe endoprosthesis at the anatomically appropriate area. The frame alsoallows for degrees of auto-adjustment towards the anatomicallyappropriate area/plane. Besides the integration of a stent and a wiremesh to form the frame of the endoprosthesis, the second most importantfeature in the invented solutions presented in the following sections isthe provision of particular components of the stent to guide and retainthe device to the anatomically correct deployment position by trackingthese components behind the native mitral valve leaflets and capturingthem wide-open (FIG. 2, 9). These components are referred to ascapturing elements. According to a preferred embodiment of the presentinvention, the capturing elements comprise a part that extends radiallybeyond the body of the wire mesh which surrounds the stent.

The valve leaflets can consist of a natural and/or synthetic materialand are being able to switch between their open and close position inresponse to the blood flow through the mitral valve. Their fixed sidesare seamed or attached with other means at the wire frame of theendoprosthesis (such as the stent ring end and the interior native valveleaflet enveloping elements). They start to function when the wire meshpart of the endoprosthesis is released.

The delivery catheter comprises a distal capsule that contains theendoprosthesis at its compressed state and the catheter shaft assemblythat extends from within the capsule to the outer system handle. Thehandle maintains control knobs and/or dials and/or buttons that areconnected to layers of the shaft assembly that on their other end withinthe capsule function to gradually open the capsule and uncover theendoprosthesis. This causes the uncovered parts of the latter to assumetheir default-uncompressed state and shape, allowing the inner lumen ofthe frame to form and the valve leaflets to commence function propelledby the blood flow. The handle also maintains functions that allowthrough shaft layers and or other components to resheath and remove theendoprosthesis even after full delivery and function is achieved.

The device allows for complete atraumatic re-capture/research andremoval of the endoprosthesis even after its full deployment andassumption of its function.

DETAILED DESCRIPTION OF THE EMBODIMENTS Embodiment 1

FIG. 1 shows a first embodiment of a prosthetic mitral valve accordingto the present invention comprising a stent (1) and a wire mesh (2)surrounding the stent at the atrial end and forming a body around thestent (2) which extends beyond the atrial end. The stent comprisesinternally three valve leaflets (3,4,5). Furthermore, the stent forms atits ventricular end a pair of capturing elements (6) which capture thenative leaflets thus providing positioning guidance andanchoring/retention.

Embodiment 2

The endoprosthesis (FIG. 2) comprises of a plurality of leaflets, whichconsist of a natural and/or synthetic material and are being able toswitch between their open and close position in response to the bloodflow through the heart. The leaflets are attached into a collapsiblewire valve frame that includes a stent (7) and a wire mesh (8). Theframe has a body that defines a lumen to its inside. The exteriorportion of the frame has features that serve for its conformation andstabilization/anchoring in the anatomic structures it contacts. When theendoprosthesis apparatus is expanded within the intended failing nativeheart valve it replaces it and resumes its function. The frame of theendoprosthesis includes a stent and a wire mesh. All these are alsodescribed in the embodiment 1.

The stent part of the endoprosthesis includes a crown (9), and a ring(10). The crown includes capturing elements for each of the native valveleaflets (11). Each such element has an exterior (12) and an interiorpart (13) for enveloping/capturing/clipping the respective native valveleaflet. The first component of the stent that expands within the leftventricle is the part of the crown that has at least two externalwings/hooks/clipping elements (14), also shown in FIG. 3A, 3B, which arethe first to appear when the ventricular part of the capsule starts toopen towards the apex of the ventricle. Once released, they are fullyexpanded. Their expansion (“opening”) is achieved by the default designof the frame as they exit the sheath and possibly from special featuresat their articulation to the rest of the frame (such as thicker areas ofthe struts close to the articulation that push away the externalelements when released, but as the frame opens these areas do notoverlap anymore and the external elements come close again to theirinternal counterparts to clip the leaflets).

These external elements when released are aligned using continuousreal-time imaging modalities, such as transesophageal echocardiography,to extend behind (outside) each of the two native mitral valve leaflets.At the same time the tips of the interior enveloping/capturing/clippingelements start to flare (15) when the ventricular side of the capsuleopens to fully release their outer counterparts. Once this is achievedthe entire system is moved so that the tips of the exteriorwings/hooks/clipping elements approach and contact the mitral valveannulus at its ventricular side. It is expected that when this occursthe operator will experience resistance providing tactile feedback forthe correct positioning. During this initial phase the native mitralvalve function is uninterrupted. The exterior elements by sitting behindthe leaflets and reaching deep into the annulus create an anchoring ofthe entire frame on the ventricular side of the mitral annulus.

Then, and while exerting a steady force to keep the externalwings/hooks/clipping parts at or as close as possible to the ventricularside of the mitral annulus, the atrial side of the capsule opensreleasing the rest of the endoprosthesis frame.

The first to be released next is the part of the stent crown that holdsthe bases of the internal enveloping/capturing/clipping elements. Theseexpand towards their external counterparts and capture/envelop/clip thenative valve leaflets locking them into a wide-open position by doingso. By pairing these hooking components on either side of the nativevalve leaflets these are engulfed/enveloped/clipped in between them andas the frame keeps expanding they are locked in this position. Theinterior pairing constituents (13) have sufficient length to capture atleast the tips of the native leaflets before they join the stent ring.They may also be made to have a progressively greater default expansiontowards the annulus (16) than their exterior counterparts, and by doingso they fix the native valve leaflets actively inside (essentially byclipping them). The pairing components can have a range of shapes thatpinch the native leaflets in between (12,13). Furthermore, the captureelements of the anterior and posterior native valve leaflets may differin shape to match the different anatomy of these leaflets. For example,the exterior elements of the anterior leaflet may be wider and longerthan their interior counterparts and have a reversed M shape so thattheir two bases are seated closer to the fibrous trigones on both sidesof the anterior leaflets (FIG. 2A).

After the stent crown is released and the native valve leaflets arelocked wide open in it, the ring of the stent is released. The stentring has a fabric skirt layer attached for sealing the areas of theannulus it apposes to from unwanted blood flow. The shape of the ringmay be rather oval and in any case resembling and conforming optimallywith the shape of the mitral valve annulus. Externally it may haveanchoring elements such as hooks, barbs, spikes, indentations or similar(17) to secure on the annulus as it apposes against it, and provideadditional stabilization of the endoprosthesis at the annulus on thisoccasion. These anchoring features are mainly found towards theperimeter of the stent that apposes to the commissural areas of theannulus. Maximal radial strength is given at the larger diameter of thestent. The radial strength of the stent arc that apposes the annulus atthe root of the anterior leaflet is calculated so that it does not pushthe leaflet into the outflow tract of the left ventricle and causeobstruction. For the same reason, the clipping mechanism of the anteriorleaflet when fully expanded may have an incline away from the outflowtract.

In the interior part of the stent ring there are elements for passivelyattaching the endoprosthesis on its delivery catheter pins during thecrimping process. This passive attachment offers stabilization of theendoprosthesis on its delivery catheter while the capsule componentsmove to release various parts of it, till of course the capsule uncoversthe area of the stent ring that sits on the catheter pins and releasesit.

The prosthetic valve leaflets are attached to the stent ring and theinterior enveloping elements of the stent crown but can also be attachedat other purposely-devoted posts of the stent (FIG. 2C).

Lastly, the wire mesh part of the endoprosthesis (8) is released bycontinued opening of the atrial side of the capsule (FIG. 3C, 3D). Thisconsists of a rather oval shaped (that in any case resembles the anatomyof the annulus) thin wire mesh that can incorporate a fabric or othermaterial to make it instantly impermeable. It is attached and is thecontinuation of the most atrial side of the stent. When released, itexpands from the native valve annulus overlapping with the stent towardsthe surrounding atrial walls. It has sufficient length to extent enoughinto the atrial side of the mitral valve annulus. By doing so stabilizesthe endoprosthesis at the atrial level of the annulus and allowsauto-adjustment of the entire endoprosthesis. It has a progressivelylarger default diameter than the atrial side of the stent, and it may bemade to have a tendency to revert backwards and appose actively to theatrial wall on the atrial side of the annulus and above it offeringsuperior sealing from paravalvular insufficiency and improving thestabilization of the entire frame. The length of the wire mesh ring candiffer locally to conform best to the anatomy it apposes to. The entiremesh wire can be braided. Alternatively, the most exterior parts of thewire mesh that are away from the annulus can be made of flat mesh, whileas it comes closer to the annulus it becomes braided.

In summary, all segments offer the stabilizing mechanism of thisendoprosthesis. The stent crown of the frame contains the pairedelements that actively capture, envelope and lock wide open the twonative valve leaflets. In addition, the bases of the exterior elementsare behind the native leaflets and are immobilized by the ventricularside of the annulus. This latter segment offers also tactile feedbackfor the correct positioning of the endoprosthesis.

The stent ring expands and apposes the native valve annulus and has alsospecial features for anchoring on it. Finally, the wire mesh offersstabilization at the level of the annulus and towards the atrial sideand locks the endoprosthesis at its final position, offering at the sametime room for self-adjustment and self-alignment.

The release of this endoprosthesis starts from the ventricle and ends inthe left atrium.

The endoprosthesis can have several standardized shapes and sizes. Itcan even be custom made based on measurements from the patient's anatomyobtained by medical imaging.

The resheath/recapture/removal capability of the endoprosthesis, evenafter complete deployment, is described in the delivery cathetersection.

Embodiment 3

Another version (FIG. 4A) of the described in the embodiment 2endoprosthesis can be deployed in the opposite way, starting from theatrial side (FIG. 4B, 4C, 4D). First, the wire mesh is graduallyreleased within the left atrium (FIG. 4B, 4C). The valve then is pulleddownward till the wire mesh seats firmly at the floor of the atrium.Then the stent ring (18) is released followed by its crown (19) thatcontains a plurality of anchoring structures (hooks, barbs, spikes,indentations or similar) (20) extending into the ventricular side of theannulus. Two of them may be seated and capture the fibrous trigones onboth sides of the anterior leaflet and hold this leaflet wide-open.Another component of the crown may extend in the middle part of theposterior leaflet (21). This is longer and therefore the last to becompletely released from the delivery system. Its final part foldscompletely backwards (22) towards the ventricular side of the annulus tocapture the posterior leaflet.

The elements for passively attaching of this endoprosthesis on itsdelivery catheter pins during the crimping process are at the mostventricular tips of the stent crown. This is the part of theendoprosthesis released last. This passive attachment offers steadinessof the endoprosthesis on its delivery catheter while the capsulecomponents move to release various parts of it, till of course thecapsule uncovers this final part.

The endoprosthesis can have several standardized shapes and sizes. Itcan even be custom made based on measurements from the patient's anatomyobtained by medical imaging. The prosthetic valve leaflets are attachedto the stent ring and the interior enveloping elements of the stentcrown but can also be attached at other areas of the wire frame.

Embodiments 4 a,b

Another version of either of the two previous embodiments (2 and 3) canhave a more dominant wire mesh part that alone or with a degree ofoverlap with the stent part apposes at the annulus and succeeds thestabilization of this endoprosthesis (FIG. 5). In the previous twoversions it was mainly the stent ring of the frame to be apposed andseated at the annulus level. In this version the wire mesh (23) occupiesa larger length of the frame of the endoprosthesis and allows it to wellreach and appose in the annulus. The stent part (24) is mostly below theannulus (FIG. 5A, 5B) but may also reach the level of the annulus andoverlap internally the wire mesh (FIG. 5C).

The wire mesh of this endoprosthesis covers from just below the annulus,then covers it and extends at the surrounding atrial walls. It has atrench or channel or concavity at its outer perimeter (25) that has theshape of the annulus and slightly oversizes it, so that by expanding onthe annulus sits on its both sides fixing perfectly and steadily theendoprosthesis.

The stent part in this case, connects to the wire mesh below the annulusand it is shorter. Alternatively, it may have a component to surroundthe wire mesh away from its outer perimeter (internally) at the level ofthe annulus and provide additional radial force to it (FIG. 5C). Then ithas a crown part extending towards the left ventricle (26) with elementsto hold or capture the native valve leaflets wide open. The stent crowncan be similar to embodiment 2, and in this case the ventricular part ofthe endoprosthesis is first deployed allowing for capturing the nativevalve leaflets, self-positioning below the annulus and anchoring andstabilization at the ventricular side. Then the rest of the stent andthe wire mesh are deployed (embodiment 4a) (FIG. 5A).

The stent crown can also be similar to embodiment 3, and in this casethe atrial part of the endoprosthesis is first deployed and pulleddownward till the wire mesh seats firmly at the floor of the atrium.Then the rest of the wire mesh is deployed surrounding the annulus andfinally the stent parts that hold or capture the native valve leafletswide-open and offer additional anchoring and stabilization at theventricular side (embodiment 4b) (FIG. 5B).

The wire mesh incorporates a fabric or other material to make itinstantly impermeable and may have a fabric skirt at the level of theannulus for better sealing. The endoprosthesis can have severalstandardized shapes and sizes. It can even be custom made based onmeasurements from the patient's anatomy obtained by medical imaging.

The prosthetic valve leaflets are attached to the wire frame of theendoprosthesis at the stent part.

Embodiment 5

This version is similar to the previous embodiment 4, but the frame ofthis endoprosthesis is entirely formed by the wire mesh (FIG. 6).

The atrial side is first released within the left atrium. The valve thenis pulled downward till the wire mesh seats firmly at the floor of theatrium. By doing so stabilizes the endoprosthesis at the atrial level ofthe annulus and allows auto-adjustment of the entire endoprosthesis. Ithas a progressively larger default diameter at its atrial side, and itmay be made to have a tendency to revert backwards and appose activelyto the atrial wall on the atrial side of the annulus and above itoffering superior sealing from paravalvular insufficiency and improvingthe stabilization of the entire frame. The dimensions of the wire meshcan differ locally to conform best to the anatomy it apposes to. Theentire mesh wire can be braided. Alternatively, the most exterior partsof the wire mesh that are away from the annulus can be made of flatmesh, while as it comes closer to the annulus it becomes braided. Thewire mesh incorporates a fabric or other material to make it instantlyimpermeable. It can also have a fabric skirt at the level of the annulusfor better sealing.

Then by keeping the opened atrial part on the floor of the atrium thepart that apposes at the annulus is released. This has a trench orchannel or concavity at its outer perimeter that has the shape of theannulus and slightly oversizes it, so that by expanding on the annulusit sits on its both sides fixing perfectly and steadily theendoprosthesis.

The wire mesh extends more into the surrounding atrial walls than in theventricular side of the annulus (FIG. 6A). The shape and dimensions ofthe atrial and ventricular parts of the mesh are such to apposecomfortably at their intended locations.

This endoprosthesis wire mesh frame may have one or more of theadditional components: A. A collapsible wire component, such a shortstent, to surround the wire mesh internally at the level of the annulusand to provide additional radial force to it at that level (27). B.Stand-alone or connected wire elements (hooks, barbs, spikes,indentations or similar) at the outer ventricular surface of the framefor anchoring below the annulus (28). C. Particular wire posts andelements for attachment of the prosthetic leaflets and for holding thenative valve leaflets wide open (29).

The wire mesh incorporates a fabric or other material to make itinstantly impermeable and may have a fabric skirt at the level of theannulus for better sealing. The endoprosthesis can have severalstandardized shapes and sizes. It can even be custom made based onmeasurements from the patient's anatomy obtained by medical imaging.

The prosthetic valve leaflets are attached to the wire frame of theendoprosthesis. This endoprosthesis can be deployed either from itsatrial or its ventricular side.

Embodiment 6

This embodiment describes an endoprosthesis, which is a version ofeither the embodiments 2-4 endoprosthesis. The main feature of thisversion that makes it distinct from those embodiments is that the stentpart of the endoprosthesis frame is dominant and occupies the majorityor the entire length of the frame, with the wire mesh part beingexterior to it forming a body around it (FIG. 7A). The lumen of theendoprosthesis is therefore defined completely by the stent, which isfully surrounded by the wire mesh.

The wire mesh (30) default shape and dimensions are to out-expand themitral valve annulus towards the atrium to allow the seating, sealingand stabilization of the endoprosthesis at its atrial side. Then thewire mesh continues as a band surrounding the stent at the annulus areaand may reach just below it. This part of the wire mesh seals theendoprosthesis at the annular level. It allows the stent to apposewithin it and compresses on the surrounding tissues offering an optimaladaptation and stabilization at this level.

The dominant stent part in this embodiment takes advantage of thegreater radial strength the stent provides to the entire frame and itallows for the formation of a uniform and assured lumien throughout theframe. The skirted stent reaches below the annulus but is short of thetips of the leaflets and its surrounding wire mesh seals any anatomicalasymmetries.

The ventricular end of the stent comprises capturing elements (31) thatoffer stabilization of the endoprosthesis at the ventricular side andholding and capturing the native valve leaflets wide open.

In case the crown of this endoprosthesis is similar to embodiments 2 or4a, the endoprosthesis is guided and navigated through the ventricle tocapture/envelope the native mitral valve leaflets and then the rest ofthe endoprosthesis is expanded towards the atrium (embodiment 6a) (FIG.7A).

In case the crown of this endoprosthesis is similar to embodiment 3 or4b, the endoprosthesis is deployed from the atrium down to the lestventricle, expanding the crown elements that trap the native mitralleaflets wide open and offer anchoring on the ventricular side of theannulus (embodiment 6b) (FIG. 7B).

The wire mesh incorporates a fabric or other material to make itinstantly impermeable and may have a fabric skirt at the level of theannulus for better sealing. The stent part that is not covered by themesh wire is skirted with a material so blocking any blood flow throughits cells/struts. The endoprosthesis can have several standardizedshapes and sizes. It can even be custom made based on measurements fromthe patient's anatomy obtained by medical imaging.

The prosthetic valve leaflets are attached to the stent of theendoprosthesis.

This endoprosthesis can be deployed either from its ventricular(embodiment 6a) or its atrial side (embodiment 6b).

Embodiment 7

This embodiment describes an endoprosthesis, which is a version of theembodiment 6 endoprosthesis. The main feature of this version that makesit distinct is that the interior capturing elements of the native mitralvalve leaflets is the stent ring itself rather than parts of its crown(FIG. 8, FIG. 9A).

The crown of the stent comprising the exterior capturing elements (32)that provide navigational guidance for the positioning and thestabilization of the endoprosthesis at the ventricular side of themitral valve annulus (first step of deployment). They expand outside ofthe native leaflets and as the endoprosthesis is pushed upwards andtowards the annulus they are captured by these elements. Then, bycontinuing the delivery of the endoprosthesis the next part of itexpanding is the stent ring itself (33) that apposes against theleaflets from their interior surface. When this occurs the native valveleaflets are captured between the stent and the its external capturingelements. Then the rest of the endoprosthesis is released. This has athin wire mesh band expanding at the level of the annulus. The wire meshthen outexpands the annulus at its atrial side offering sealing andstabilization. The most ventricular end of the stent may be wiremesh-free (FIG. 8, FIG. 9B).

The endoprosthesis described is deployed from its ventricular sideupwards and towards the atrium (embodiment 7a).

To avoid possible prolapse of the stent into the outflow of the leftventricle, a shorter part of the stent crown and its interior capturingelements (as described in endoprosthesis 6) may be preserved especiallyin the arc of the annulus that apposes towards the native anteriormitral leaflet (34).

In case the crown of this endoprosthesis is similar to embodiment 3, theendoprosthesis is deployed from the atrium down to the lest ventricle,expanding the crown elements that trap the native mitral leaflets wideopen and offer anchoring on the ventricular side of the annulus(embodiment 7b).

The wire mesh incorporates a fabric or other material to make itinstantly impermeable and may have a fabric skirt at the level of theannulus for better sealing. The stent part that is not covered by themesh wire is skirted with a material so blocking any blood flow throughits cells/struts.

The endoprosthesis can have several standardized shapes and sizes. Itcan even be custom made based on measurements from the patient's anatomyobtained by medical imaging.

The prosthetic valve leaflets are attached to the stent of theendoprosthesis.

This endoprosthesis can be deployed either from its ventricular side asdescribed (embodiment 7a) or its atrial side (embodiment 7b).

The Delivery Catheter

1. Retrograde Access (Transventricular/Transapical)

The delivery catheter for the endoprosthesis of all embodiments consistsof the capsule (FIG. 10,35) that contains the collapsed endoprosthesis,the shaft (36) and the handle (37). They all share a central lumen (38)that accommodates the guide wire over which the device is railed at theintended position of deployment.

The capsule contains the crimped endoprosthesis. Both of its ends areconical (39) to allow smooth tracking.

For the endoprosthesis of the embodiments 1, 2 and 4a the capsule opensin two parts (FIG. 3, FIG. 10) the atrial part that is longer (40) andthe ventricular part that is shorter (41). Each of these parts can moveand open/close the respective part of the capsule independently. Firstthe ventricular part is opened (withdrawn/pulled back) the part of theendoprosthesis crimped in this part expands (FIG. 3A, 3B), namely theoutside capturing elements of the native valve leaflet expand fully,while their internal counterparts start to flare. When the externalcapturing/anchoring components are positioned deep behind the nativeleaflets and if possible in contact to the ventricular side of theannulus, the atrial part of the capsule is opened (advanced/pushed)releasing gradually first the internal native leaflet capturingelements, and then the stent ring and the wire mesh that appose to theannulus and towards the surrounding atrial wall (FIG. 3C, 3D).

When the endoprosthesis is fully deployed and functional it is stillconnected to the delivery catheter with a plurality of thin wires (suchas ultra thin nitinol wires) (42), or screwing wires attached at themost ventricular edge of the stent (area connecting the external andinternal capturing elements). Therefore complete atraumatic removal ofthe endoprosthesis is still feasible. When thin wires are used, they arethreaded trough the stent. If the endoprosthesis position and functionis satisfactory, one end of the thin wire is pulled till the entirethread is removed from the endoprosthesis and releases it. If theendoprosthesis needs to be removed both ends of the thin wires arepulled together. Another way of reversible connection of the thin wiresto the stent is with Highwayman's knots, that allow tightening the knotand tugging by pulling one end of the wire, while the knot unties easilyby pulling the other end of the wire.

Finally, an alternative way of attachment is by use of screwing wiresthat are fixed in female parts found at the stent end.

The part of the shaft traveling inside through the capsule has an innerhollow to accommodate the guide wire (38). The shaft of this lumenallows the push and opening of the atrial segment of the capsule. Anadditional shaft layer travels the capsule and the endoprosthesis iscrimped on it. This layer has a plurality of pins at the level of thestent ring (43) on which the stent is passively stabilized by mirroringelements at its exterior surface.

The ventricular segment of the capsule is connected to an additionalshaft layer (44) that is found on the delivery system (not in thecapsule). A part of this layer starting at the capsule and havingsufficient length can effortlessly expand to accommodate a part of theendoprosthesis in case it needs to be removed after complete deployment.This is required because the ventricular segment of the capsule issmaller and cannot accommodate the entire length of the collapsing stentand wire mesh. The entire length of the endoprosthesis needs to besheathed in order the atrial capsule part to come close, meet and attachits ventricular part and the entire capsule safely removed.

When the delivery is considered successful and the holding wires areremoved, the empty atrial capsule segment is withdrawn to meet andattach to the also empty ventricular capsule segment and then thecapsule is closed and removed in one piece (FIG. 3D).

The shaft of the delivery system that connects the capsule to the handlehas the previously described layers plus a space (could be in the formof an additional lumen) to accommodate the retracting holding wires ofthe endoprosthesis (45).

The handle is where all the above-described components of the shaftculminate. It has a central lumen for the guide wire to exit (46) andall the necessary knobs/dials/wheels (47) to facilitate the independentmotions of the two capsule segments, and the thin wires that are used toresheath and remove the valve if needed. It is envisaged that oneknob/dial/wheel is required for the movement of the atrial capsule, onefor the movement of the ventricular capsule and possibly one for thepulling of the holding wires.

The delivery catheter is advanced in the left ventricle by itself orthrough a guide sheath. The guide sheath and/or the delivery cathetercan have flexing capabilities to assist the coaxial and central to theannulus positioning of the capsule before and during delivery.

Considering the endoprostheses of the embodiments 3, 4b and 5 thedelivery catheter is similar, but the capsule does not split into twoparts, and it opens from its atrial tip towards the ventricle (theendoprosthesis of the embodiment 1 can also be released such a way)(FIG. 4B, 4C, 4D). First, the wire mesh is released completely withinthe atrium. The entire device then is pulled downward till the wire meshseats firmly at the floor of the atrium. Then the capsule is furtherwithdrawn releasing gradually the wire frame that apposes to the annulusand the crown components of the stent part in embodiments 3 and 4b orthe ventricular part of the wire mesh in the embodiment 5.

The wire frame of the endoprosthesis and the course of the anchoringstructures allow for complete retrieval of the endoprosthesis even aftercomplete release.

The unnecessary parts of the delivery catheter for delivering thisendoprosthesis are omitted (such as the separate shaft layer for thestabilization pins of the endoprosthesis and the handle wheel for movingthe atrial segment of the capsule). A plurality of holding wires forretrieval of the endoprosthesis is reversibly attached (as describedbefore) at the tips of the anchoring or other structures of the stentcrown. By pulling these, the endoprosthesis reenters into the deliverycapsule.

FIGS. 11 and 12 illustrate an example of transapical delivery of one ofthe embodiments described.

2. Antegrade Access (Transeptal, or Direct Approach)

The delivery catheter for the endoprosthesis of all embodiments consistsof the endoprosthesis capsule, the shaft and the handle (FIG. 13). Theyall share a central lumen that accommodates the guide wire over whichthe device is railed at the intended position of deployment.

The capsule contains the collapsed and crimped endoprosthesis. Its bothends are conical to allow smooth tracking forward and backward.

For the endoprosthesis of the embodiments 1, 2 and 4a the capsule opensin two parts, the atrial part is longer and the ventricular part isshorter (FIG. 14). Each of these parts can move and open/close therespective part of the capsule independently. First the ventricular partis opened (advanced/pushed) and the part of the endoprosthesis crimpedin this part expands, namely the external capturing elements of thenative valve leaflets expand fully, while their internal counterpartsstart to flare. When the external capturing elements are positioned deepbehind the native leaflets and in contact to the ventricular side of theannulus, the atrial part of the capsule is opened (withdrawn/pulledback) releasing gradually first the internal capturing elements of thestent crown, then the stent ring and finally the wired mesh. When theendoprosthesis is fully deployed and functional it is still connected tothe delivery catheter with a plurality of thin wires (such as ultra thinnitinol wires) or screwing wires attached at the most atrial edges ofthe wire mesh. Therefore complete atraumatic removal of theendoprosthesis is still feasible. When thin wires are used, they arethreaded trough suitable features of the wire mesh. If theendoprosthesis position and function is satisfactory, one end is pulledtill the entire thread is removed from the endoprosthesis and releasesit. If the endoprosthesis needs to be removed both ends of the nitinolwires are pulled, and it is gradually retracted into the atrial capsule.Another way of reversible connection of the thin wires to the mesh iswith the Highwayman's knot that allows tightening the knot and tuggingby pulling one end of the wire, while the knot unties easily by pullingthe other end of the wire.

Finally, an alternative way of attachment is by use of screwing wiresthat are fixed in female parts in the mesh.

The part of the shaft traveling inside through the capsule has an innerlumen to accommodate the guide wire. The shaft of this lumen allows thepush and opening of the ventricular segment of the capsule. Anadditional shaft layer travels the capsule and the endoprosthesis iscrimped on it. This layer has a plurality of pins at the level of thestent ring on which the stent is passively stabilized by mirroringelements at its exterior surface.

The atrial segment of the capsule is connected to an additional shaftlayer that is found on the delivery system (not in the capsule). Thiswithdraws the atrial segment of the capsule, to completely release theendoprosthesis.

A part of this layer starting at the capsule and having sufficientlength can effortlessly expand to accommodate a part of theendoprosthesis in case this needs to be removed after completedeployment. This is required because the entire length of theendoprosthesis needs to be sheathed into the atrial segment of thecapsule. This additional space is required for the length of the stentthat used to be accommodated into the ventricular capsule. The entirelength of the endoprosthesis needs to be sheathed into the atrialcapsule for the ventricular capsule segment to attach and close thecapsule for safe removal.

If the deployment is not satisfactory, the wire mesh is first resheathedinto the longer atrial capsule. The small part of the endoprosthesisthat used to be accommodated into the ventricular capsule is alsoretracted into the atrial capsule, as described. When the delivery isconsidered successful and the holding wires are removed, the emptyventricular capsule segment is withdrawn to meet and attach to the alsoempty atrial capsule segment and they are then removed en block.

The shaft of the delivery system that connects the capsule to the handlehas the previously described layers plus a space (could be in the formof an additional lumen) to accommodate the holding/retracting wires ofthe endoprosthesis.

The handle is where all the above-described components of the shaftculminate. It has a central lumen for the guiding wire to exit and allthe necessary knobs/dials to facilitate the independent motions of thetwo capsule segments, and the wires that can be used to resheath andremove the valve if needed. It is envisaged that one knob/dial isrequired for the movement of the atrial capsule, one for the movement ofthe ventricular capsule and possibly one for the pulling of the holdingwires.

The delivery catheter is advanced in the left atrium through atranseptal sheath or with direct access. The transeptal sheath and/orthe delivery catheter can have flexing capabilities to assist thecoaxial and central to the annulus positioning of the capsule before andduring delivery.

Considering the endoprostheses of the embodiments 3, 4b and 5, thedelivery catheter is similar, but the capsule does not split into twoparts, and it opens from its atrial tip towards the ventricle (theendoprosthesis of the embodiment 1 can also be released such a way)(FIG. 4B, 4C, 4D). First, the wire mesh is released completely withinthe atrium by advancing the capsule towards the ventricle. The entiredevice then is pushed downward till the wire mesh seats firmly at thefloor of the atrium. Then the capsule is further advanced releasinggradually the rest of the wire frame that apposes to the annulus and thecrown components of the stent part in embodiments 3 and 4 or theventricular part of the wire mesh in the embodiment 5.

The wire frame of the endoprosthesis and the course of the anchoringstructures allow for complete retrieval of the endoprosthesis even aftercomplete release.

A plurality of holding wires for retrieval of the endoprosthesis isreversibly attached (as described before) at the atrial edges of thewire mesh. By pulling these, the endoprosthesis reenters into the atrialsegment of the delivery capsule.

FIGS. 15 and 16 illustrate an example of transapical delivery of one ofthe embodiments described.

In summary, the claimed inventions provide for all aspects of asuccessful transcatheter prosthetic mitral valve. They resolve theproblems related to the uneven anatomy of the mitral valve by offeringremedies at the level of the mitral valve leaflets (capture in awide-open position and stabilization at the ventricular side), at thelevel of the annulus (optimal apposition, sealing and stabilization bythe prosthetic valve frame) and at the level of the atrial floor(optimal apposition, sealing and stabilization by the prosthetic valveframe).

These are achieved with: 1. A refined combination of two components inthe frame of the endoprosthesis, namely the wire stent contributingoptimal radial strength for the formation of the frame lumen and theorifice of the prosthetic valve and the wire mesh contributingplasticity and optimal conformation. 2. An innovative method to captureand immobilize the native valve leaflets and navigationally guides thedeployment of the prosthetic valve offering tactile feedback and at thesame time the much-required stabilization at the ventricular level.

The invention claimed is:
 1. A prosthetic mitral valve for transcatheterdelivery comprising: a collapsible and self-expandable interior stenthaving an atrial end and a ventricular end, the interior stent having asealing skirt and defining a lumen supporting a plurality of valveleaflets; and a collapsible and self-expandable exterior wire meshsurrounding the interior stent, the exterior wire mesh extending alongsubstantially an entire length of the interior stent, the exterior wiremesh having a lower radial strength than the interior stent forconforming to a native mitral valve, the exterior wire mesh attached atleast to at the atrial end and forming a body around the stent, theexterior wire mesh having a first portion with an enlarged diametersized for placement above a mitral annulus for sealing and stabilizingthe prosthetic mitral valve on an atrial side, the exterior wire meshhaving a second portion with a reduced diameter for contacting themitral annulus and for extending to a ventricular side of the mitralannulus; wherein the stent forms at its ventricular end a plurality ofnative leaflet capturing elements, the capturing elements extending in aventricular direction beyond a ventricular end of the exterior wire meshand then turning in an atrial direction such that the capturing elementsare positioned radially outwardly from the exterior wire mesh, thecapturing elements adapted for trapping native mitral leaflets againstthe wire mesh and for anchoring the prosthetic mitral valve on aventricular side.
 2. The prosthetic mitral valve according to claim 1,wherein the wire mesh extends longitudinally towards the ventricular endof the stent forming a body around the stent.
 3. The prosthetic mitralvalve according to claim 2, wherein the wire mesh reaches theventricular end of the stent.
 4. The prosthetic mitral valve accordingto claim 2, wherein the wire mesh extends beyond the ventricular end ofthe stent.
 5. The prosthetic mitral valve according to claim 1, whereinsizes of the native leaflet capturing elements vary between them.
 6. Theprosthetic mitral valve according to claim 1, wherein shapes of thenative leaflet capturing elements vary between them.
 7. The prostheticmitral valve according to claim 1, wherein the wire mesh comprises asealing material.
 8. The prosthetic mitral valve according to claim 7,wherein the sealing material is a fabric.
 9. The prosthetic mitral valveaccording to claim 1, wherein the wire mesh comprises at its outersurface barbs or spikes.
 10. The prosthetic mitral valve according toclaim 1, wherein the stent is made of collapsible nitinol, or stainlesssteel.
 11. The prosthetic mitral valve according to claim 1, wherein thewire mesh is made of collapsible nitinol or stainless steel.
 12. Acatheter for delivery of the prosthetic mitral valve according to claim1, further comprising a capsule, a shaft and a handle.